"It's too distracting, what with all the games, apps, 4Gs, web-browsing, Twitters, and IMs" - That's a terrible reason not to get one. It assumes that laptops are somehow less distracting and trust me, they aren't. I can't tell you how often I see people on FB or other websites in class. In fact, sometimes in undergrad, I saw people watching movies on their notebooks (why even come to class?).
"What makes it desirable to your kid is what makes it desirable to criminals" - The figures for notebook theft must be astronomical because we get reminded constantly not to leave our notebooks unguarded. How is an iPad any different?
"It's meant for the enjoyment of one person, which means social seclusion" - That's just plain ludicrous.
"Digital text books are a marvel, but there's no secondary market" - This I actually agree with. Used textbooks are not only dirt cheap but much more enjoyable to read. More importantly, they're easier to markup.
"It'll already be Old Technology by the time you buy it" - So is a notebook.
Some of those reason are just plain ridiculous. I do agree with the sentiment though. It should not be a replacement for a real computer despite the potential it has. Especially for those in specialized fields, an iPad would be a good accoutrement.